An antenna is usually connected to a transmitter or receiver by way of a feed line. Antennas for use at radio frequencies are effective over a limited frequency range. When operation is required over a wide frequency range it is common to use multiple antennas with each antenna optimized for a specific narrow band of frequencies. However, in such an antenna system for each antenna an individual feed line is to be provided so that such a system is costly, room consuming and heavy and, thus, less suitable for automotive applications.
Also common are systems in which multiple (active) antennas are connected to multiple receivers and/or transmitters via a single feed line. Signals of multiple antennas operated in different frequency ranges are combined by way of cross-over networks that superimpose signals in different frequency ranges to provide a broadband signal on a single feed line (e.g., multi-standard antenna systems), and signals of multiple antennas operated in the same frequency range (e.g., antenna diversity systems) are combined in a weighted fashion to provide an optimized signal in the particular frequency range which is to be transferred via the single feed line. However, if multi-standard antenna systems are arranged in a vehicle, in which usually receiving conditions vary strongly, the frequency response of the crossover networks may be either mismatched to the off air channel or the receiver may overloaded to the effect that the signals received are disturbed or the crossover networks produce too much noise due to little signal amplitudes.
Thus, there is a need to provide a multi-standard antenna/receiver system that overcomes the above-mentioned drawbacks.